\(2Cu+O_2\rightarrow2CuO\)

\(n_{Cu}=\dfrac{6,4}{64}=0,1mol\)

\(n_{O_2}=\dfrac{1,12}{22,4}=0,05mol\)

=> hai chất tác dụng vừa đủ

\(m_{oxit}=0,1.80=8g\)

Fansipan is the highest peak of Vietnam, Laos and Cambodia, so it is called "the Roof of Indochina" while the local (1)......people.......call it Huasipan. Huasipan means large tottering rock.

Fansipan is 3,143 metres (2).....high......It is in Lao Cai Province, nine kilometres southwest of Sa Pa Town (3).....in......the Hoang Lien Son mountain range.

Fansipan is now one of the very few eco-tourist spots of Vietnam, with about 2,024 varieties of plants and 327 types of animal and insects. Many tourist (4).......climb......the mountain every year. If you climb the mountain from the end of February to march, you (5)....will.......have a chance to admire the beautiful blooming flowers in many different colors.

 Circle the word whose underlined part is pronunced differently from others      

A. condition           B. ocean                      C.  sugar             D. pleasure

Complete the sentences with was or were

 1. My grandparents   have         married for more than 50 years.

 2. When I      was       in Berlin last year, the weather    was    very cold

 3. How many people   are    there at the party?

 4. Where    do  you on Saturday evening?

 5. It    is   a beutiful day in August. My family and I   are    on holiday at the seaside.

 6.      is      George at school today?

 7. How   does    your first day at work?

 8. It     is     very nice to meet you, Mr. Brown  

111111

\(n_{H_2}=\dfrac{8,96}{22,4}=0,4mol\)

Gọi số mol Fe và Al lần lượt là: x và y

\(Fe+H_2SO_4\rightarrow FeSO_4+H_2\)

x            x                  x       x

\(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)

y             1,5y                               1,5y

Ta có:

\(\left\{{}\begin{matrix}56x+27y=11\\x+1,5y=0,4\end{matrix}\right.\)                \(\Leftrightarrow\left\{{}\begin{matrix}x=0,1\\y=0,2\end{matrix}\right.\)

\(\%m_{Fe}=\dfrac{0,1.56}{11}.100\%=50,9\%\)

\(\%m_{Al}=100\%-50,9\%=49,1\%\)

Khối lượng của Oxi là:

\(m_{KL}+m_{Oxi}=m_{oxit}\)

\(\Leftrightarrow m_{oxi}=31-23=8g\)

Ta có:

\(M_M+3\left(M_O+M_H\right)=78\)

\(\Leftrightarrow M_M+51=78\)

\(\Rightarrow M_M=27\)

=> B

What do you do if you want to (1)............ a book in a library? If you know the author's (2)............, go to the author catalogue. Find the title of the book (3)............ check the shelf mark. Make a note of this before you look(4)..................the appropriate shelf. If you do not know the author's name, go to the (5)................... Catalogue. If there (6)................ no title catalogue in the library, go to the subject catalogue. Check all the titles which are under the (7)........... you want. Then check the appropriate card, as with the author catalogue. Next look for the book on the shelf. Let the librarian stamp it (8).................... you take it out of the library. If the book isn't on the shelf, ask the librarian to get it for you.

1. A. find B. look C. take D. make

2. A. address B. title C. name D. age

3. A. and B. or C. but D. so

4. A. at B. for C. after D. on

5. A. title B. author C. subject D. shelf

6. A. be B. are C. is D. was

7. A. subject B. book C. index D. title

8. A. after B. before C. when D. if